Q After installing a trial version of Parallels, then Windows 8 on that, it works fine when using my user account. When another user logs in using their account, Parallels refuses to run the VM, asking for the install disk to be inserted. Do I need to install Windows for each user, or is this a limitation in my trial version?
A You sound to have installed the Virtual Machine for Parallels, into which you then installed Windows, in a folder to which only the one user has access permissions; that is its normal default.
You may need to buy a copy of Parallels to support full functions, but provided that the Parallels application is in your main Applications folder, and its supporting files are in your main Library folder (rather than the Library in your Home folder) it should work for all user accounts on your Mac.
You can move your existing Virtual Machine folder from ~/Documents/Parallels to a commonly-accessible location on your Mac. The logical place would be in /Users/Shared, where there is probably already a Parallels folder. However some users experience problems with that folder’s unusual permissions, and it might be worth putting directly into /Users, perhaps.
Then start Parallels up. It will invite you to create a Virtual Machine, as it will initially be unable to find your existing one. Open its Preferences dialog, and in the General pane set the new location for the Virtual Machines folder.
You should also ensure that other user accounts have admin privileges if they are to use Parallels fully, so that it can manage files such as its virtual drives. Remember that other users will not even be able to see the contents of your home folder.
Updated from the original, which was first published in MacUser volume 28 issue 12, 2012.